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- /** @file
- CPUID Leaf 0x15 for Core Crystal Clock frequency instance of Timer Library.
- Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
- SPDX-License-Identifier: BSD-2-Clause-Patent
- **/
- #include <Base.h>
- #include <Library/TimerLib.h>
- #include <Library/BaseLib.h>
- #include <Library/PcdLib.h>
- #include <Library/DebugLib.h>
- #include <Register/Cpuid.h>
- GUID mCpuCrystalFrequencyHobGuid = {
- 0xe1ec5ad0, 0x8569, 0x46bd, { 0x8d, 0xcd, 0x3b, 0x9f, 0x6f, 0x45, 0x82, 0x7a }
- };
- /**
- Internal function to retrieves the 64-bit frequency in Hz.
- Internal function to retrieves the 64-bit frequency in Hz.
- @return The frequency in Hz.
- **/
- UINT64
- InternalGetPerformanceCounterFrequency (
- VOID
- );
- /**
- CPUID Leaf 0x15 for Core Crystal Clock Frequency.
- The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX.
- In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported.
- @return The number of TSC counts per second.
- **/
- UINT64
- CpuidCoreClockCalculateTscFrequency (
- VOID
- )
- {
- UINT64 TscFrequency;
- UINT64 CoreXtalFrequency;
- UINT32 RegEax;
- UINT32 RegEbx;
- UINT32 RegEcx;
- //
- // Use CPUID leaf 0x15 Time Stamp Counter and Nominal Core Crystal Clock Information
- // EBX returns 0 if not supported. ECX, if non zero, provides Core Xtal Frequency in hertz.
- // TSC frequency = (ECX, Core Xtal Frequency) * EBX/EAX.
- //
- AsmCpuid (CPUID_TIME_STAMP_COUNTER, &RegEax, &RegEbx, &RegEcx, NULL);
- //
- // If EAX or EBX returns 0, the XTAL ratio is not enumerated.
- //
- if ((RegEax == 0) || (RegEbx == 0)) {
- ASSERT (RegEax != 0);
- ASSERT (RegEbx != 0);
- return 0;
- }
- //
- // If ECX returns 0, the XTAL frequency is not enumerated.
- // And PcdCpuCoreCrystalClockFrequency defined should base on processor series.
- //
- if (RegEcx == 0) {
- CoreXtalFrequency = PcdGet64 (PcdCpuCoreCrystalClockFrequency);
- } else {
- CoreXtalFrequency = (UINT64)RegEcx;
- }
- //
- // Calculate TSC frequency = (ECX, Core Xtal Frequency) * EBX/EAX
- //
- TscFrequency = DivU64x32 (MultU64x32 (CoreXtalFrequency, RegEbx) + (UINT64)(RegEax >> 1), RegEax);
- return TscFrequency;
- }
- /**
- Stalls the CPU for at least the given number of ticks.
- Stalls the CPU for at least the given number of ticks. It's invoked by
- MicroSecondDelay() and NanoSecondDelay().
- @param Delay A period of time to delay in ticks.
- **/
- VOID
- InternalCpuDelay (
- IN UINT64 Delay
- )
- {
- UINT64 Ticks;
- //
- // The target timer count is calculated here
- //
- Ticks = AsmReadTsc () + Delay;
- //
- // Wait until time out
- // Timer wrap-arounds are NOT handled correctly by this function.
- // Thus, this function must be called within 10 years of reset since
- // Intel guarantees a minimum of 10 years before the TSC wraps.
- //
- while (AsmReadTsc () <= Ticks) {
- CpuPause ();
- }
- }
- /**
- Stalls the CPU for at least the given number of microseconds.
- Stalls the CPU for the number of microseconds specified by MicroSeconds.
- @param[in] MicroSeconds The minimum number of microseconds to delay.
- @return MicroSeconds
- **/
- UINTN
- EFIAPI
- MicroSecondDelay (
- IN UINTN MicroSeconds
- )
- {
- InternalCpuDelay (
- DivU64x32 (
- MultU64x64 (
- MicroSeconds,
- InternalGetPerformanceCounterFrequency ()
- ),
- 1000000u
- )
- );
- return MicroSeconds;
- }
- /**
- Stalls the CPU for at least the given number of nanoseconds.
- Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
- @param NanoSeconds The minimum number of nanoseconds to delay.
- @return NanoSeconds
- **/
- UINTN
- EFIAPI
- NanoSecondDelay (
- IN UINTN NanoSeconds
- )
- {
- InternalCpuDelay (
- DivU64x32 (
- MultU64x64 (
- NanoSeconds,
- InternalGetPerformanceCounterFrequency ()
- ),
- 1000000000u
- )
- );
- return NanoSeconds;
- }
- /**
- Retrieves the current value of a 64-bit free running performance counter.
- Retrieves the current value of a 64-bit free running performance counter. The
- counter can either count up by 1 or count down by 1. If the physical
- performance counter counts by a larger increment, then the counter values
- must be translated. The properties of the counter can be retrieved from
- GetPerformanceCounterProperties().
- @return The current value of the free running performance counter.
- **/
- UINT64
- EFIAPI
- GetPerformanceCounter (
- VOID
- )
- {
- return AsmReadTsc ();
- }
- /**
- Retrieves the 64-bit frequency in Hz and the range of performance counter
- values.
- If StartValue is not NULL, then the value that the performance counter starts
- with immediately after is it rolls over is returned in StartValue. If
- EndValue is not NULL, then the value that the performance counter end with
- immediately before it rolls over is returned in EndValue. The 64-bit
- frequency of the performance counter in Hz is always returned. If StartValue
- is less than EndValue, then the performance counter counts up. If StartValue
- is greater than EndValue, then the performance counter counts down. For
- example, a 64-bit free running counter that counts up would have a StartValue
- of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
- that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
- @param StartValue The value the performance counter starts with when it
- rolls over.
- @param EndValue The value that the performance counter ends with before
- it rolls over.
- @return The frequency in Hz.
- **/
- UINT64
- EFIAPI
- GetPerformanceCounterProperties (
- OUT UINT64 *StartValue OPTIONAL,
- OUT UINT64 *EndValue OPTIONAL
- )
- {
- if (StartValue != NULL) {
- *StartValue = 0;
- }
- if (EndValue != NULL) {
- *EndValue = 0xffffffffffffffffULL;
- }
- return InternalGetPerformanceCounterFrequency ();
- }
- /**
- Converts elapsed ticks of performance counter to time in nanoseconds.
- This function converts the elapsed ticks of running performance counter to
- time value in unit of nanoseconds.
- @param Ticks The number of elapsed ticks of running performance counter.
- @return The elapsed time in nanoseconds.
- **/
- UINT64
- EFIAPI
- GetTimeInNanoSecond (
- IN UINT64 Ticks
- )
- {
- UINT64 Frequency;
- UINT64 NanoSeconds;
- UINT64 Remainder;
- INTN Shift;
- Frequency = GetPerformanceCounterProperties (NULL, NULL);
- //
- // Ticks
- // Time = --------- x 1,000,000,000
- // Frequency
- //
- NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
- //
- // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
- // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
- // i.e. highest bit set in Remainder should <= 33.
- //
- Shift = MAX (0, HighBitSet64 (Remainder) - 33);
- Remainder = RShiftU64 (Remainder, (UINTN)Shift);
- Frequency = RShiftU64 (Frequency, (UINTN)Shift);
- NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
- return NanoSeconds;
- }
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